JPH05261606A - Extensive cam lock locking chuck - Google Patents

Abstract

PURPOSE:To hold a wide variety of works different in diameter strongly with a cam face as well as to reduce the frequency of reprogramming for a chuck. CONSTITUTION:A claw cartridge 15 is detachably installed in a spindle, and plural pieces of chuck jaws 18 are supported on this cartridge rockably by a fulcrum shaft 17. A hydraulic cylinder 11 turning a ring 6 in one direction and a spring 13 turning it in reverse both are installed, and these chuck jaws 18 are opened or closed via those of on-off pins 10 and jaw arms 20 with the turning of the ring 6. Each cam face 22 coming into contact with an outer diameter of a work W at a specified wedge angle is installed in the chuck jaws 18, and each of the cam faces 22 is made up into a form comprising a lot of points where the wedge angle is constant and a distance from the jaw rocking center is gradually changed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cam lock chuck for gripping a work by means of cam surfaces provided on a plurality of chuck claws, and more particularly to a wide range cam lock chuck constructed so as to grip various kinds of works having different outer diameters. Is.

[0002]

2. Description of the Related Art Generally, a cam lock chuck is mounted on a spindle having a work centering center. The cam lock chuck includes a plurality of chuck claws that can swing about an axis parallel to the main shaft, and each chuck claw is provided with a cam surface that comes into contact with the outer diameter of the workpiece at a predetermined wedge angle. As shown in FIG. 4, in the conventional cam lock chuck, a cam center O is provided at a position eccentric from the swing center A of the chuck claw 41 by a distance E, and the cam center O is provided along a circular arc with a radius L. A surface 42 is formed. The wedge angle β at the contact point C between the cam surface 42 and the work W is determined based on the friction coefficient between the chuck claw 41 and the work W, and
A strong wedge force is generated between the cam surface 42 and the outer peripheral surface of the work W to prevent the chuck claw 41 from slipping during heavy grinding or heavy cutting, so that the driving force of the spindle can be reliably transmitted to the work W. It is like this. In the figure, the arrows indicate the rotation directions of the spindle and the work.

[0003]

However, according to the conventional cam lock chuck, the cam surface 42 has the chuck claw 41.
Since it is formed in a part of a circular arc eccentric from the swing center A, when the gripping diameter R of the work W changes, the wedge angle β of the contact point C changes accordingly. Therefore, in order to grip the work W with the optimum wedge angle β, it is necessary to prepare many kinds of dedicated chuck claws corresponding to the diameter of the work W and replace them each time the kind of the work changes. There was a problem that the setup change work of was very troublesome. In addition to the cam lock chuck, a nipper chuck that can handle a change in gripping diameter of about 1.5 mm has been conventionally known, but this chuck is configured such that the nipper grips a work by the force of a spring. Therefore, the gripping force is limited, and it is not suitable for heavy grinding or heavy cutting.

SUMMARY OF THE INVENTION An object of the present invention is to provide a wide range cam lock chuck capable of gripping various kinds of works having different diameters strongly and applicable to heavy grinding or heavy cutting.

[0005]

In order to solve the above-mentioned problems, the cam lock chuck of the present invention has a plurality of chuck claws swingably supported around an axis parallel to the main shaft and has a predetermined wedge angle. Is provided with a cam surface in contact with the outer diameter of, and the cam surface is formed in a shape including a large number of points having a constant wedge angle and a gradual change in distance from the claw swing center.
Further, preferably, the plurality of chuck claws are supported so as to be movable with respect to the center of the claw swing. Further, a claw opening / closing mechanism that simultaneously opens and closes a plurality of chuck claws and a claw cartridge that supports each chuck claw are provided, and the claw cartridge is detachably mounted on the spindle separately from the claw opening / closing mechanism.

[0006]

According to the cam lock chuck of the present invention, since the cam surface is formed in the above-mentioned shape, an arbitrary point on the cam surface is always in contact with the outer diameter of the work at a constant wedge angle. Therefore, it is possible to strongly grip various kinds of works having different diameters by one kind of chuck claw with an optimum wedge angle, and reduce the number of times of chuck setup change. Further, since each chuck claw is supported movably with respect to the swing center of the claw, even if the outer diameter dimension of the grip portion of the workpiece is not uniform, the chuck claw moves in the radial direction according to the outer diameter dimension, All cam surfaces can be reliably brought into contact with the work. Moreover, since the claw cartridge supporting the chuck claws is detachably mounted on the main shaft, the setup change operation can be easily performed when processing a work having a diameter exceeding the grippable range.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 and 2, a spindle stock 1 having a centering center 2 is rotatably mounted on a spindle stock 1 of a grinder or a lathe, and a cam lock chuck 4 of this embodiment is mounted on the front end thereof. . The cam lock chuck 4 is provided with a body 5 coupled to the main shaft 3, a ring 6 is rotatably supported on the outer periphery of the body 5, is fixed by a face plate 7, and is prevented by a spring 13 in the counterclockwise direction in FIG. Being energized. A top 8 and a pin block 9 are attached to the ring 6 at three equal positions.
An opening / closing pin 10 is provided at the front of the opening. A hydraulic cylinder 11 is installed on the headstock 1, and the hydraulic cylinder 1
1, a spring 13, a ring 6 and the like constitute a pawl opening / closing mechanism, and the rod 12 of the hydraulic cylinder 11 pushes the top 8 to rotate the ring 6 clockwise in FIG. A proximity switch 14 detects the stop position of the spindle 3.

A pawl cartridge 15 is joined to the front surface of the face plate 7 and is detachably mounted on the main shaft 3 by a plurality of drive bolts 16 separately from the pawl opening / closing mechanism. A support shaft 17 is provided in parallel with the axis of the main shaft 3 at three equally divided positions of the pawl cartridge 16, and a chuck pawl 18 is supported on each support shaft 17 through a large-diameter hole 19 so as to be swingable and idle. There is. A claw arm 20 is coupled to each chuck claw 18, and a slit 21 that fits into the opening / closing pin 10 is formed here. The chuck claw 18 is opened and closed by the rotation of the ring 6 by the engagement of the open / close pin 10 and the slit 21. The fully open position of the chuck claw 18 is shown by a chain line in FIG.

Each chuck claw 18 is provided with a cam surface 22 which comes into contact with the outer diameter of the work W at a predetermined wedge angle. In this embodiment, the cam surface 22 has a wedge angle β as shown in FIG. It is formed in a shape including a large number of contact points C0 to Cn that are constant and that the distances L0 to Ln from the claw swing center A gradually change. In FIG. 3, D is the work W from the center A of the claw swing.
To the center B of the workpiece, Δθ is a minute angle for indexing the contact points C0 to Cn, 2R0 is the diameter of the workpiece W gripped at the contact point C0 (distance L0), and 2R1 is the workpiece gripped at the contact point C1 (distance L1). The diameter of W, 2Rn, is the diameter of the workpiece W gripped at the contact point Cn (distance Ln), and Ln and Rn for each indexing minute angle Δθ are obtained by the following equation.

[0010]

[Equation 1]

The operation of the cam lock chuck constructed as described above will be explained. When opening and closing the chuck claw 18, first, the main shaft 3 is stopped at a fixed angle by the proximity switch 14 and is prevented from rotating by an external force after the stop. A spindle drive motor (not shown) is braked. Next, the rod 12 of the hydraulic cylinder 11 is projected, and the ring 6 is swung against the spring 13 via the top 8. With this, the claw arm 20 and the chuck claw 18 are in the fully open position around the support shaft 17. The work W is detached in this state. Subsequently, when the rod 12 of the hydraulic cylinder 11 is retracted, the ring 6 is swung in the opposite direction by the spring 13, and the chuck claws 18 are closed, so that the cam surfaces 2 of the chuck claws 18 are closed.
2 contacts the outer diameter of the work W at the wedge angle β.

In this case, since the cam surface 22 is formed in the above-described shape, an arbitrary point on the cam surface 22 is the work W.
Contact with a constant wedge angle β with respect to the outer diameter of. Therefore, a wide variety of workpieces having a diameter difference of about 10 mm or workpieces that require reversal processing with gripping portions having different diameters at both ends are strongly gripped by the chuck wedge 18 of one kind at the optimum wedge angle β. Therefore, it is possible to reduce the number of times of exchanging the chuck, and it is possible to perform heavy grinding or heavy cutting without trouble. Further, since each chuck claw 18 is movably supported on the support shaft 17 corresponding to the claw swing center A, even if the outer diameter of the gripping portion of the work W is not uniform, the chuck claw 18 can be adjusted according to the outer diameter. The chuck jaws 18 move in the radial direction, and all the cam surfaces 22 can be surely brought into contact with the work W, which is safe. Moreover, in the cam lock chuck of this embodiment, the pawl cartridge 15 that supports the chuck pawl 18 is detachably attached to the main spindle 3 separately from the pawl opening / closing mechanism including the hydraulic cylinder 11 spring 13, the ring 6, and the like. Therefore, the setup change operation when processing the work W having a diameter exceeding the grippable range can be extremely facilitated. The present invention is not limited to the above-described embodiments, and the shapes and configurations of the respective portions can be appropriately modified and embodied without departing from the spirit of the present invention.

[0013]

As described in detail above, according to the invention of claim 1, the cam surface of the chuck claw has a large number of points where the wedge angle is constant and the distance from the center of the claw swing gradually changes. Since it is formed with a shape including, it is possible to strongly grip various types of workpieces with different diameters, reduce the number of times of chuck changeover, and exert an excellent effect that heavy grinding or heavy cutting can be performed without trouble. .

According to the second aspect of the present invention, since each chuck claw is movably supported with respect to the swinging center of the claw, even if the outer diameters of the gripping parts of the work are not uniform, all the cam surfaces are covered by the work. There is an effect that it can be surely contacted.

[Brief description of drawings]

FIG. 1 is a front view of a cam lock chuck showing an embodiment of the present invention.

FIG. 2 is a sectional view of the cam lock chuck of FIG.

3 is an explanatory view showing a cam surface shape of the chuck claw of FIG. 1. FIG.

FIG. 4 is an explanatory diagram showing a cam surface shape of a conventional cam lock chuck.

[Explanation of symbols] 1- ・ Main spindle stock, 2 ・ ・ Centering center, 3 ・ ・ Spindle, 4 ・
・ Cam lock chuck, 5 ・ ・ body, 6 ・ ・ ring,
7 ... Face plate, 8 ... Top, 9 ... Pinplock, 10 ...
・ Opening / closing pin, 11 ・ ・ Hydraulic cylinder, 12 ・ ・ Rod,
13 ... Spring, 14 ... Proximity switch, 15 ... Claw cartridge, 16 ... Drive bolt, 17 ... Support shaft, 1
8 ・ ・ Chuck claw, 19 ・ ・ Large diameter hole, 20 ・ ・ Claw arm, 21 ・ ・ Slit, 22 ・ ・ Cam surface, W ・ ・ Workpiece.

Claims (2)

[Claims] 1. A plurality of chuck claws swingably supported around an axis parallel to a main shaft is provided with a cam surface which comes into contact with the outer diameter of a work at a predetermined wedge angle, and the cam surface has a constant wedge angle. A wide range cam lock chuck characterized in that it is formed in a shape including a large number of points where the distance from the claw swing center gradually changes. 2. A wide range cam lock chuck according to claim 1, wherein a plurality of chuck claws are supported so as to be movable with respect to a center of claw swing.